No evidence of hacking has emerged involving Murdoch's U.S. operations, a suite of properties that includes not just Fox News, but also the New York Post and the Wall Street Journal.

Susan Sarandon, the panel's moderator, did not weigh in on the hacking issue, although she said that she knew she had been the target of government surveillance. She said that she had her phone tapped and recently had trouble getting security clearance to go to the White House.

As might be expected, the more than an hour-long panel discussion between two of Hollywood's most prominent liberals dealt with a range of political topics such as teacher unions, the upcoming presidential election and the Occupy Wall Street movement, in addition to the craft of documentary filmmaking.

When it came to the current contest between President Barack Obama and Mitt Romney, Moore said that he believed that Republicans were engaging in voter suppression because they feared that the majority of Americans were supportive of the president's policies.

"Why would Republicans want to limit the number of people voting if they believe this is a conservative country," Moore said.

It wasn't just the GOP who drew Moore's ire. The director was unsparing in his criticism for fellow documentary filmmaker Davis Guggenheim's acclaimed "Waiting for 'Superman.'"

Moore said he hated the 2010 film, which is sharply critical of teacher unions.

He said that the film picks the wrong villain, and argued that not enough resources are being diverted to public education.

"Morale is horrible," Moore said of public school teachers.

Sarandon agreed that the teachers were being unfairly scapegoated for the country's fiscal problems when blame should rest with other expenditures like foreign wars.

"Teachers are the unsung heroes," Sarandon said.

Beyond their shared attraction to leftist causes, Moore said that he and Sarandon had another common bond — they are both introverts.

Moore said that his natural shyness could be a hindrance when it came to filming gotcha moments in his films, where he corners Republican lawmakers, health insurance company higher-ups or corporate executives and grills them on camera. He said that before every confrontational interview he need to psych himself up by remembering the political issues at stake.

"I'm trying to convince myself that I'm going to get through this alive…but I'm always terrified," Moore said.

"I'm not inclined to beat through the CEOs' doors," he added.

He said he often felt bad for his subjects, even Charlton Heston, the late actor and National Rifle Association president he cornered so memorably in his 2002 documentary about gun control, "Bowling for Columbine." After the interview ended with Heston walking out, having made some racially insensitive comments, Moore said his cameraman started to cry.